Spectrum Map: Toward Predicting the Spatial Distribution of Spectrum Usage in CRNs

Recent measurements on radio spectrum usage have revealed the abundance of under-utilized bands of spectrum that belong to licensed users. Prior knowledge about occupancy of such bands and corresponding achievable performance metrics can potentially help secondary networks to devise effective strategies to improve utilization. In this paper, we use Shepard's method of interpolation to create a spectrum map that provides a spatial distribution of spectrum usage over a region of interest. It is achieved by intelligently fusing the spectrum usage reports shared among the secondary nodes at various locations. We further use this spectrum usage distribution to estimate different radio and network performance metrics like channel capacity, network throughput, spectral efficiency and bit error rate. Through simulation experiments we show the correctness of the prediction model and how it can be used by secondary networks for strategic positioning of secondary pairs and selecting candidate channels.